{
    "mode": "man",
    "parameter": "dnsblog",
    "section": "8postfix",
    "url": "https://www.chedong.com/phpMan.php/man/dnsblog/8postfix/json",
    "generated": "2026-10-07T21:07:06Z",
    "synopsis": "dnsblog [generic Postfix daemon options]",
    "sections": {
        "NAME": {
            "content": "dnsblog - Postfix DNS allow/denylist logger\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "dnsblog [generic Postfix daemon options]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "The  dnsblog(8) server implements an ad-hoc DNS allow/denylist lookup service. This may even‐\ntually be replaced by an UDP client that is built directly into the postscreen(8) server.\n",
            "subsections": []
        },
        "PROTOCOL": {
            "content": "With each connection, the dnsblog(8) server receives a DNS allow/denylist domain name, an  IP\naddress, and an ID.  If the IP address is listed under the DNS allow/denylist, the dnsblog(8)\nserver  logs the match and replies with the query arguments plus an address list with the re‐\nsulting IP addresses, separated by whitespace, and the reply TTL.  Otherwise it replies  with\nthe  query  arguments  plus  an  empty address list and the reply TTL; the reply TTL is -1 if\nthere is no reply, or a negative reply that contains no SOA record.  Finally, the  dnsblog(8)\nserver closes the connection.\n",
            "subsections": []
        },
        "DIAGNOSTICS": {
            "content": "Problems and transactions are logged to syslogd(8) or postlogd(8).\n",
            "subsections": []
        },
        "CONFIGURATION PARAMETERS": {
            "content": "Changes  to  main.cf are picked up automatically, as dnsblog(8) processes run for only a lim‐\nited amount of time. Use the command \"postfix reload\" to speed up a change.\n\nThe text below provides only a parameter summary. See postconf(5) for more details  including\nexamples.\n",
            "subsections": [
                {
                    "name": "config_directory (see 'postconf -d' output)",
                    "content": "The default location of the Postfix main.cf and master.cf configuration files.\n"
                },
                {
                    "name": "daemon_timeout (18000s)",
                    "content": "How  much time a Postfix daemon process may take to handle a request before it is ter‐\nminated by a built-in watchdog timer.\n"
                },
                {
                    "name": "postscreen_dnsbl_sites (empty)",
                    "content": "Optional list of DNS allow/denylist domains, filters and weight factors.\n"
                },
                {
                    "name": "ipc_timeout (3600s)",
                    "content": "The time limit for sending or receiving information  over  an  internal  communication\nchannel.\n"
                },
                {
                    "name": "process_id (read-only)",
                    "content": "The process ID of a Postfix command or daemon process.\n"
                },
                {
                    "name": "process_name (read-only)",
                    "content": "The process name of a Postfix command or daemon process.\n"
                },
                {
                    "name": "queue_directory (see 'postconf -d' output)",
                    "content": "The location of the Postfix top-level queue directory.\n"
                },
                {
                    "name": "syslog_facility (mail)",
                    "content": "The syslog facility of Postfix logging.\n"
                },
                {
                    "name": "syslog_name (see 'postconf -d' output)",
                    "content": "A  prefix  that is prepended to the process name in syslog records, so that, for exam‐\nple, \"smtpd\" becomes \"prefix/smtpd\".\n\nAvailable in Postfix 3.3 and later:\n"
                },
                {
                    "name": "service_name (read-only)",
                    "content": "The master.cf service name of a Postfix daemon process.\n"
                }
            ]
        },
        "SEE ALSO": {
            "content": "smtpd(8), Postfix SMTP server\npostconf(5), configuration parameters\npostlogd(8), Postfix logging\nsyslogd(8), system logging\n",
            "subsections": []
        },
        "LICENSE": {
            "content": "The Secure Mailer license must be distributed with this software.\n",
            "subsections": []
        },
        "HISTORY": {
            "content": "This service was introduced with Postfix version 2.8.\n\nAUTHOR(S)\nWietse Venema\nIBM T.J. Watson Research\nP.O. Box 704\nYorktown Heights, NY 10598, USA\n\nWietse Venema\nGoogle, Inc.\n111 8th Avenue\nNew York, NY 10011, USA\n\nDNSBLOG(8postfix)",
            "subsections": []
        }
    },
    "summary": "dnsblog - Postfix DNS allow/denylist logger",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "smtpd",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/smtpd/8/json"
        },
        {
            "name": "postconf",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/postconf/5/json"
        },
        {
            "name": "postlogd",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/postlogd/8/json"
        },
        {
            "name": "syslogd",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/syslogd/8/json"
        }
    ]
}